Fracture zones in the equatorial Atlantic and the breakup of western Pangea

Journal Article · Mon Jun 01 00:00:00 EDT 1987 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1987)15<533:FZITEA>2.0.CO;2· OSTI ID:5276452

Jones, E J.W.

The early breakup of western Pangea has been investigated by mapping the pattern of fracture zones and distribution of seismic reflectors within the sedimentary cover of the Atlantic between the Cape Verde Islands and the equator. Two distinct sets of transverse oceanic lineaments are present, separated by the Guinea Fracture Zone near lat 10/sup 0/N. Lineaments to the north are associated with the formation of the central Atlantic in the Late Jurassic and Early Cretaceous; those in the south relate to the Cretaceous opening of the South Atlantic. The Guinea Fracture Zone is thus the conjugate of the Jurassic transform boundary under peninsular Florida, which linked the Atlantic with the Gulf of Mexico. The distribution of dated seismic reflectors suggests that deposition of deep-water sediments was confined to the region north of the Guinea transform until Aptian time, when the Sierra Leone Basin began to open. The latter started to widen at least 15 m.y. after the initiation of the Cape Basin off southwest Africa, an age difference that can be explained if a short-lived plate boundary developed in either Africa or South America during the Early Cretaceous. Neither the trends of the equatorial fracture zones nor the seismic stratigraphy supports the existence of a predrift gap between west Africa and Brazil.

• Research Organization: Univ. College London (England)
• OSTI ID: 5276452
• Journal Information: Geology; (United States), Vol. 15:6
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ATLANTIC OCEAN
SEA BED
GEOLOGIC FRACTURES
AGE ESTIMATION
CRETACEOUS PERIOD
JURASSIC PERIOD
LINEAMENTS
MAGNETIC SURVEYS
NORTHERN HEMISPHERE
PLATE TECTONICS
SEDIMENTS
SEISMIC SURVEYS
EARTH PLANET
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MESOZOIC ERA
PLANETS
SEAS
SURFACE WATERS
SURVEYS
TECTONICS
580100* - Geology &amp; Hydrology- (-1989)